public class FindNum { public static boolean findANum(int[][] array, int target) { int row = array.length;//行数 int cloumn = array[0].length;//列数 int i = 0; int j = cloumn - 1; boolean found = false; while(i <= row-1 && j >= 0) { if(target < array[i][j]) { j--; } if(target > array[i][j]) { i++; } if(target == array[i][j]) { found = true; break; } } return found; } public static void main(String[] args) { int a[][] = {{1,2,8,9},{2,4,9,12},{4,7,10,13}}; System.out.println(a.length); System.out.println(a[0].length); System.out.println(findANum(a, 7)); } }